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fix: make a separate server connection for each database in config and route client connections properly #14

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fix: make a separate server connection for each database in config and route client connections properly #14

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12 changes: 8 additions & 4 deletions frontendConnection.go
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Original file line number Diff line number Diff line change
Expand Up @@ -8,8 +8,8 @@ import (
"github.com/johto/notifyutils/notifydispatcher"
"github.com/lib/pq"

"bytes"
"bufio"
"bytes"
"crypto/rand"
"errors"
"fmt"
Expand Down Expand Up @@ -59,6 +59,7 @@ type FrontendConnection struct {

stream *fbcore.MessageStream
dispatcher *notifydispatcher.NotifyDispatcher
dispatchers map[string]*notifydispatcher.NotifyDispatcher

connStatusNotifier chan struct{}
notify chan *pq.Notification
Expand Down Expand Up @@ -92,11 +93,11 @@ func RejectFrontendConnection(c net.Conn) {
_ = c.Close()
}

func (c FrontendConnection) String() string {
func (c *FrontendConnection) String() string {
return c.remoteAddr
}

func NewFrontendConnection(c net.Conn, dispatcher *notifydispatcher.NotifyDispatcher, connStatusNotifier chan struct{}) *FrontendConnection {
func NewFrontendConnection(c net.Conn, dispatchers map[string]*notifydispatcher.NotifyDispatcher, connStatusNotifier chan struct{}) *FrontendConnection {
io := &frontendConnectionIO{
c: c,
bufw: bufio.NewWriterSize(c, 128),
Expand All @@ -106,7 +107,8 @@ func NewFrontendConnection(c net.Conn, dispatcher *notifydispatcher.NotifyDispat
remoteAddr: c.RemoteAddr().String(),

stream: fbcore.NewFrontendStream(io),
dispatcher: dispatcher,
dispatcher: nil,
dispatchers: dispatchers,

connStatusNotifier: connStatusNotifier,
notify: make(chan *pq.Notification, 256),
Expand Down Expand Up @@ -172,6 +174,8 @@ func (c *FrontendConnection) auth(dbcfg VirtualDatabaseConfiguration, sm *fbprot
return authFailed("3D000", "database %q does not exist", dbname)
}

c.dispatcher = c.dispatchers[dbname]

switch authMethod {
case "trust":
return true
Expand Down
82 changes: 45 additions & 37 deletions main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -132,47 +132,55 @@ func main() {
var m sync.Mutex
var connStatusNotifier chan struct{}

listenerStateChange := func(ev pq.ListenerEventType, err error) {
switch ev {
case pq.ListenerEventConnectionAttemptFailed:
elog.Warningf("Listener: could not connect to the database: %s", err.Error())

case pq.ListenerEventDisconnected:
elog.Warningf("Listener: lost connection to the database: %s", err.Error())
m.Lock()
close(connStatusNotifier)
connStatusNotifier = nil
m.Unlock()
// make sure pq.Listener doesn't pick up any env variables
os.Clearenv()

case pq.ListenerEventReconnected,
pq.ListenerEventConnected:
elog.Logf("Listener: connected to the database")
m.Lock()
connStatusNotifier = make(chan struct{})
m.Unlock()
dispatchers := make(map[string]*notifydispatcher.NotifyDispatcher)

for _, value := range Config.Databases {
dbname := value.name

listenerStateChange := func(ev pq.ListenerEventType, err error) {
switch ev {
case pq.ListenerEventConnectionAttemptFailed:
elog.Warningf("Listener: could not connect to database %s: %s", dbname, err.Error())

case pq.ListenerEventDisconnected:
elog.Warningf("Listener: lost connection to database %s: %s", dbname, err.Error())
m.Lock()
close(connStatusNotifier)
connStatusNotifier = nil
m.Unlock()

case pq.ListenerEventReconnected,
pq.ListenerEventConnected:
elog.Logf("Listener: connected to database %s", dbname)
m.Lock()
connStatusNotifier = make(chan struct{})
m.Unlock()
}
}
}

// make sure pq.Listener doesn't pick up any env variables
os.Clearenv()
clientConnectionString := fmt.Sprintf("fallback_application_name=allas %s dbname=%s", Config.ClientConnInfo, dbname)
listener := pq.NewListener(
clientConnectionString,
250*time.Millisecond, 3*time.Second,
listenerStateChange,
)
listenerWrapper, err := newPqListenerWrapper(listener)
if err != nil {
elog.Fatalf("%s", err)
}
nd := notifydispatcher.NewNotifyDispatcher(listenerWrapper)
nd.SetBroadcastOnConnectionLoss(false)
nd.SetSlowReaderEliminationStrategy(notifydispatcher.NeglectSlowReaders)

clientConnectionString := fmt.Sprintf("fallback_application_name=allas %s", Config.ClientConnInfo)
listener := pq.NewListener(
clientConnectionString,
250*time.Millisecond, 3*time.Second,
listenerStateChange,
)
listenerWrapper, err := newPqListenerWrapper(listener)
if err != nil {
elog.Fatalf("%s", err)
}
nd := notifydispatcher.NewNotifyDispatcher(listenerWrapper)
nd.SetBroadcastOnConnectionLoss(false)
nd.SetSlowReaderEliminationStrategy(notifydispatcher.NeglectSlowReaders)
dispatchers[value.name] = nd

// We don't strictly speaking need to be pinging the server; this is a
// workaround for PostgreSQL BUG #14830.
go listenerPinger(listener)
// We don't strictly speaking need to be pinging the server; this is a
// workaround for PostgreSQL BUG #14830.
go listenerPinger(listener)
}

for {
c, err := l.Accept()
Expand All @@ -194,7 +202,7 @@ func main() {
}
m.Unlock()

newConn := NewFrontendConnection(c, nd, myConnStatusNotifier)
newConn := NewFrontendConnection(c, dispatchers, myConnStatusNotifier)
go newConn.mainLoop(Config.StartupParameters, Config.Databases)
}
}